1. Field of the Invention
The present invention relates to tanks and systems for containing and maintaining aquatic life. More particularly, the invention relates to systems for introducing fresh water, aerating the water and withdrawing used water with respect to a containment vessel or formation.
2. Background of the Related Art
It is often necessary or desirable to transport or maintain a small quantity of aquatic life in a small container. For example, the use of live bait, such as minnows or shrimp, for fishing requires that a container be used to transport a sufficient amount of bait for a day long fishing trip. It is preferred that the container provide sufficient aeration and fresh water for the bait during this period. Another example is the collection of live marine animals, such as crabs or shrimp, for personal consumption or resale to distributors or restaurants. It is most desirable to transport and maintain shrimp or other marine life in a container that provides sufficient oxygen and fresh water for the marine life to stay alive and well until just before consumption.
Over a short period of time such as one day, it is generally necessary to provide the marine life with a sufficient amount of aerated or oxygenated water. Typically, a container is filled with water and aerated with a device such as a bubble tube. When using a small fishing or shrimping boat, the container may take the form of a common cooler or refrigeration box comprising a plastic shell with a hinged lid. These coolers vary in size, but typically a water-filled cooler may be moved by one or two individuals from a boat to the dock and into a truck. Furthermore, in commercial shrimping or fishing operations, the container for storing marine life may be significantly larger and perhaps comprise a portion of the vessel's hull. Certainly, the capacity of the oxygenating device will vary in proportion to the size of the container and the population of marine life to be maintained.
If the population of marine life maintained in the container is high relative to the size of the container and the amount of water contained therein, then it is necessary to periodically replace the water with fresh water due to the increase in the concentration of waste products. The operation of removing and replacing the water may be accomplished through a number of methods. With small containers or coolers, this operation may include manually bailing water with a bucket or tipping the container over the side of the boat. Both of these methods, and other similar methods, are inefficient and require hard work. Furthermore, these methods involve a risk that some or all of the marine life will be swept from the container along with the water or otherwise lost during the operation.
In commercial applications, the exchange of water may be accomplished by using separate intake and outlet pumps to supply and discharge water, respectively. These two pumps may be provided in addition to one or more aerating devices. However, using intake and discharge pumps requires some means for turning the pumps on and off, such as manual switches requiring operator intervention or water level sensors which communicate with a controller that dictates operation of the pumps. However, having two pumps, an aerator and a control system increases the cost of the system and requires additional maintenance, not to mention more complex operation.
Therefore, there is a need for a system that will aerate water and replace the water periodically. Preferably, such a system should be simple and require little, if any, electronic controls. It would be desirable if the system could be adapted for use in any size of container, both personal or commercial. It would also be desirable if the system utilized less equipment and operated efficiently on standard electrical sources.